GB1603664A - Fly-off strander - Google Patents

Description

PATENT SPECIFICATION ( 11)

( 21) Application No 15911/78 ( 22) Filed 21 Apr 1978 l ( 31) Convention Application No 792980 ( 32) Filed 2 May 1977 in ( 33) United States of America (US) ( 44) Complete Specification Published 25 Nov 1981 ( 51) INT CL 3 DO 7 B 3/06 II 7/00 ( 52) Index at Acceptance D 1 T 2 B 1 A 1 2 B 7 2 BX 2 ( 54) FLY-OFF STRANDER ( 71) We, CEECO MACHINERY MANUFACTURING LIMITED, a corporation organised and existing under the laws of Ontario, Canada, of 2180 Highway 7, Concord, Ontario, Canada L 4 K 113, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the

following statement:

This present invention generally relates to cable or wire stranders.

When manufacturing a cable from a plurality of wires, a core wire formed by either a single wire or a plurality of already stranded wires is usually passed through the machine and other wires are wrapped around the core wire either while the core wires move along its path or at the end of the machine This function is usually carried out by high speed machines which, as a rule, include one or more rotatable frames or housings and a plurality of wire-carrying bobbins located within the frame or carried by supports mounted on the frames.

The core wire is usually paid-off from a bobbin mounted outside the frame and passed through the frame through a path either along the axis of rotation of the frame or displaced from the axis of rotation of the frame The way the core wire is handled characterizes the type of wire strander and its application.

If the core wire is passed through the machine along its axis of rotation, the wire carrying bobbins rotate around it and the wires paid-off are wound on the core wire at several points along the machine This system allows the manufacture of conductors with a high number of wires and a change in direction of the various layers since the machine is composed of many sections independent of each other Furthermore, since the core wire passes substantially along the axis of the machine, a large multi-stranded core can be used.

If the core wire is passed through the machine along a path significantly displaced from the axis of rotation of the frame, the wire carrying bobbins are positioned inside the frame along its axis of rotation and they remain stationary while the frame rotates.

The cable wires are paid-off from the bobbins and the wires pass through a path displaced from the axis of rotation of the machine and are wound around the core at the end of the machine This method allows the manufacture of conductors with a relatively low number of wires and the various layers of the stranded conductors must be wound in the same direction.

In the manufacturing of stranded cable from a plurality of wires, three basic types of stranders are presently used in the industry.

In one type, the tubular strander, the bobbins are placed in cradles which are mounted on bearings in a tubular rotatable frame or housing During the operation, the frame rotates while the cradles and the bobbins are stationary The wires are paidout or pulled from the bobbins and arwe brought along the frame through guides until they are wound on the core wire which is usually taken from a bobbin mounted outside the frame and passed through the frame along a path that is parallel to the axis of the machine, but significantly displaced from the center as are the other wires paid-out from the bobbins loaded on the cradles inside the tubular frame Such a strander is shown and described in the products catalog published by Ceeco Machinery Manufacturing Limited of Concord, Ontario, Canada.

The second basic type of strander is known as a rigid strander In this type of strander, the bobbins are usually mounted on a rigid rotatable frame and they are solidly connected to the frame itself, this machine is usually made in sections and 1 603 664 ( 19)) 1 603 664 follows the classic stranding formations of conductors made with wires of the same diameters In the basic formation, each layer above the core wire has six more wires than the previous one Thus, the first layer directly on the core wire has six wires, the second wire layer has twelve wires, the fourth wire layer has eighteen wires, the fifth wire layer has twenty-four wires, etc.

While rigid stranders are generally slower than tubular stranders, they are more compact and are normally used to manufacture conductors of nineteen or more wires, especially in the non-ferrous industry For conductors with a lower number of wires, tubular stranders are adopted as a rule, in view of their higher speeds Rigid stranders are also shown and described in the aboveidentified Ceeco Machinery Manufacturing Limited catalog.

The third type of strander commonly used is called a planetary strander and, in many respects, is similar to the rigid strander.

However, in the planetary strander the bobbins are mounted on cradles which are kept in a fixed plane through mechanical means while the machine rotates The object of such stranding operation is to avoid any twisting of the wire during the stranding operation as is done when using a rigid frame strander Planetary stranders are also shown and described in the above Ceeco catalog Tubular stranders and planetary stranders do not twist the base wire during the operation and, therefore, can be used both in the ferrous and non-ferrous industries Rigid frame stranders are used as a rule only when the base wire can be subject to twisting.

In the past, wire carrying bobbins mounted on the frame of the strander have usually been mounted so that the bobbins were required to rotate along their longitudinal axis in order to pay-off the wire This arrangement usually requires some control of the rotation of the bobbins, such as a brake mechanism for each bobbin to provide the required wire tension and to assure that the bobbins will not continue to rotate when the frame of the strander has stopped its rotation.

The braking device causes the tension of the wire paid-off from the bobbins to vary during the operation of the strander since the wire pulling tension required to make the bobbin rotate is differnt when the bobbin is full or near empty If the initial braking force is adjusted for a full bobbin, the same braking force applied to a bobbin with partially depleted wire supply is sometimes sufficient to cause unacceptable stretch, especially for wires of the smaller gauge In such a case, the cable produced will be malformed Also, since the braking force is applied to each bobbin before the initial start of the strander, there is a tendency to stretch the wire before the strander reaches its normal operational speed Because of frequent malfunction of the brakes, the wires from the bobbins within the frame of the strander occasionally continue to pay-out after the strander has been stopped, and because different brake forces are applied to different bobbins, different tensions are created in the wire paid-out from the bobbins Therefore, many times the cables formed by traditional stranders have one or more wires loosely wrapped with the remaining wire more tightly wrapped.

One attempt to overcome some of the above-mentioned problems was to fly-off the wires from stationary bobbins since this provided a better means of controlling the tension irrespective of the amount of wire remaining on the bobbin A fly-off system was introduced for stranders having a core wire path significantly displaced from the axis of rotation of the machine and the wire carrying bobbins positioned within the tubular frame with longitudinal axes both parallel and perpendicular to the axis of rotation of the frame For example, in United States Patent No 3,827,225, for "High Speed Strander", both a tubular and a rigid strander are disclosed wherein the wires fly off bobbins which are mounted on shafts parallel to the axis of the machine rotating frame With respect to the tubular strander disclosed in the above patent, the bobbins are positioned along the axis of rotation of the tubular, cylindrical frame and, therefore, the core wire cannot pass through the axis of rotation, but is displaced therefrom as in conventional tubular stranders This presents a disadvantage inasmuch as it limits the size of the core wire which may be used.

With respect to the rigid strander disclosed in the above patent, wherein the core wire passes along the axis of rotation of the frame and where the bobbins are mounted on the frame with their longitudinal axes approximately parallel to the axis of the machine, the rigid strander disclosed has several disadvantages because, while the wire flies off during rotation of the frame, it is subject to significant variations in centrifugal forces which tend to push the wire outwardly, thus creating oscillations of the wire tension.

This is particularly severe when using large bobbins as is the case in the industry, since such tension variations may result in fluctuations in tightness of the finished stranded product Another disadvantage of the rigidtype strander disclosed in the above patent is that the bobbins must be mounted on cantilvered shafts parallel to the axis of rotation, thus limiting the size of bobbins that can be used or causing a severe reduction in the speed of the machine since large 1 603 664 bobbins and high speeds would subject the cantilevered shaft to excessive stresses The disclosed configuration also requires that the bobbins be positioned far from the axis of rotation, thus increasing the centrifugal forces that come into play In order to maintain the same total number of bobbins while decreasing the radial distances at which the shafts are mounted from the axis of rotation, the overall length of the machine may have to be increased to an undesirable or impractical length.

Another fly-off, tubular-type strander is disclosed in United States Patent No.

3,902,307 for "Modified High Speed Strander" This patent discloses a tubular-type strander which includes a hollow cylindrical housing or tube inside which a plurality of bobbins are supported along the axis of rotation of the cylindrical housing With this strander, the bobbins are situated on the axis of rotation to avoid significant centrifugal forces thereon Consequently, as with standard tubular stranders, the core wire cannot go through the center or axis of rotation of the frame or housing, but must be bent or deflected at least four times as the core wire is guided along the axis, and thence along the housing wall, and finally moved towards the housing axis Such displacement of the core wire from the axis of rotation, as suggested above, limits the size of the core wire which can be used and, therefore, limits the size of the overall product which can be handled or produced by the strander.

In the tubular-type strander disclosed in both of the above-identified patents, the bobbin supporting stems or shafts are pivotally connected to the cylindrical housings by means of pivot arrangements to permit the bobbins to be loaded and removed through relatively small openings in the tubular or cylindrical housings Such constructions have made these stranders more complicated, and more inconvenient to use.

According to the present invention a strander comprises a rotatable strander body, a plurality of wire pay-off bobbins supported outside the axis of rotation of the strander body, means for advancing a core wire along said axis of rotation, wire-guides for directing wires paid-off from the bobbins to a direction substantially parallel to the said axis of rotation arranged proximate to each pay-off bobbin, a frame connected to said body and including at least one portion supported for rotation about said axis of rotation, said supported portion or portions being spaced from the strander body and including securing means for fixing the pay-off bobbins to said portion or portions the pay-off bobbins being fixed against rotation about their individual axes and extending inwardly from the supported portion or portions.

In order that the invention may be more fully understood an embodiment in accordance therewith will now be described, by way of example only, with reference to the accompanying drawing which shows a tubular strander shaft of body 12 arranged to rotate about its longitudinal axis 14 A plurality of wire pay-off bobbins 26, only one of which is shown for convenience, are mounted outside the axis of rotation A core wire 22 is advanced along the axis of rotation by known means (not shown) Wire guides 63,44 (described below) direct wires paid off from the bobbin 26 to a direction substantially parallel to the axis of rotation.

A frame portion 60 is connected to body 12 to rotate therewith and includes a portion b spaced from body 12 and supported for rotation about the axis of rotation The portion 60 b includes securing means 62 for fixing the pay-off bobbin thereto As described below the pay-off bobbins are fixed against rotation about their axes and, in the embodiment, extend inwardly from portions b such that an extension of their individual axes intersect the axis of rotation and are substantially normal thereto.

It is to be understood that the fly-off mode is that which occurs in any system where the wire is paid off from a stationary bobbin, i e a bobbin which does not rotate about its own axis.

The frame member generally designated by 60 is, as mentioned above, mounted on the shaft 12 for rotation therewith about axis 14 The frame member includes, by way of illustration only, a pair of end plates or members 60 a as well as the transverse or cross member constituting portion 60 b, which is spaced from and generally parallel to the axis of rotation as shown The securing means provided in the form of hook members or devices are fixedly mounted on portion 60 b to position the bobbin between the shaft 12 and the portion b.

Although, for convenience only one transverse or cross member is shown, it will be appreciated that a plurality of portions b may be present uniformly angularly spaced from each other about the axis of rotation, and rigidly joined to one another.

The arrangement of bobbins may include rows thereof extending generally in a direction parallel to the axis of rotation The supported portions will be provided with a plurality of securing means for securing the pay-off bobbins thereto, as shown for the pay-off bobbin illustrated in the drawing.

The securing means may be arranged to secure at least two pay-off bobbins, each being on a different supported portion with their individuala axes in a common plane.

The embodiment shown in the drawing 1 603 664 utilizes a rotating guide and tensioning system 63 which is mounted on a bearing 54, which is itself fixedly mounted on the shaft 12 through the supporting housing or structure 61.

The rotating guide and tensioning system 63 generally comprises an elongate arm 63 a, along the length of which there are provided two or more guiding sheaves or pulleys 63 b-63 d The free end of the arm 63 a extends to a generally intermediate position along the longitudinal length of the bobbin.

The rotating guide and tensioning system must be balanced as symmetrically as possible by use, for example, by use of counterweights 63 e or any other suitable compensating method, so that it does not show preferential positional patterns when rotating around its own axis in the centrifugal force field created by the rotation of the main shaft 12 around the axis 14.

An adjustable brake 56 may also be used to dampen the rotational movements of the rotating tensioning and guide system 63 so that the tension and this rate at which wire is paid off the bobbom can be adjustably controlled.

In operation, the embodiment shown causes the wire 34 a to fly-off or be paid-off in a generally radially inward direction under the action of external forces acting on the wire, as indicated by the arrow Under the action of the external pulling forces acting on the wire 34 a, the rotating guide and tensioning system begins to rotate, thus allowing the wire 34 to become unwound from the stationary bobbin 26 under a constant tension controlled by the brake 56.

During such unwinding, the wire 34 a is guided along the arm 63 a by means of the pulleys 63 b-63 d and caused to enter the support structure or housing 61 through the hole or eyelet 61 a Inside the support structure or housing 61, there is provided a pulley 44 which redirects the wire 34 a in a direction parallel to the axis of rotation of the shaft 12, and the wire 34 a subsequently leaves the housing 61 through a hole or eyelet 61 b as shown.

In this manner, the wire 34 is paid-off the bobbins 26 and advanced to one end or take-up end of the shaft 12 and there, applied to this core wire 22 in a conventional way.

While the arrangement shown in the drawing is the presently preferred one, other arrangements may also be possible which mount the bobbins on a support or frame portion 60 The specific guide and tensioning devices or arrangements are not critical and any conventional means for guiding and tensioning a wire which is unwound from a bobbin mounted as shown may be used

Claims (9)

WHAT WE CLAIM IS: 65

1 A strander comprising a rotatable strander body, a plurality of wire pay-off bobbins supported outside the axis of rotation of the strander body, means for advancing a core wire along said axis of rotation, 70 wire guides for directing wires paid-off from the bobbins to a direction substantially parallel to the said axis of rotation arranged proximate to each pay-off bobbin, a frame connected to said body and including at 75 least one portion supported for rotation about said axis of rotation, said supported portion or portions being spaced from the strander body and including securing means for fixing the pay-off bobbins to said portion 80 or portions, the pay-off bobbins being fixed against rotation about their individual axes and extending inwardly from the supported portion or portions.

2 A strander according to Claim 1, in 85 which the wire-guides comprise a flyer and a first pulley wheel.

3 A strander according to Claim 1 or Claim 2, in which a plurality of supported portions are angularly spaced from each 90 other about said axis of rotation, said supported portions being rigidly joined to one another.

4 A strander according to Claim 3, in which the angular spacing of said supported 95 portions is uniform.

A strander according to any one of the preceding claims, in which the or each supported portion is provided with a plurality of securing means for securing a row of 100 wire pay-off bobbins, said row extending generally in a direction parallel to said axis of rotation.

6 A strander according to any one of the preceding claims, in which a plurality of 105 supported portions are provided which are angularly spaced from each other about said axis, and said securing means are arranged to secure at least two pay-off bobbins, each being on a different supported portion with 110 their individual axes in a common plane.

7 A strander according to Claim 2 or any one of Claims 3 to 6 when dependent upon Claim 2, in which each flyer comprises an elongate arm, a portion of which is at a 115 position outside the bobbin and generally intermediate the axial ends of the bobbin, and a plurality of pulley wheels spaced from each other along said elongate arm to guide wire from a respective bobbin to said first 120 pulley wheel.

1 603 664 5

8 A strander according to Claim 7, further comprising adjustable braking means for applying a controllable braking force so that the tension and the rate at which wire is paid-off the bobbin can be adjustably controlled.

9 A strander, substantially as described with reference to the accompanying drawing.

For the Applicants.

LLOYD WISE, TREGEAR & CO, Chartered Patent Agents, Norman House, 105-109 Strand, London, WC 2 R OAE.

Printed for Her Majesty's Stationery Office.

by Croydon Printing Company Limited, Croydon Surrey 1981.

Published by The Patent Office 25 Southampton Buildings.

London WC 2 A IAY from which copiet may be obtained.